Re: [PATCH] iio: adc: ad7173: fix num_slots on most chips

[Jonathan Cameron <Jonathan.Cameron@huawei.com>]

On Thu, 03 Jul 2025 17:16:31 -0500
David Lechner <dlechner@baylibre.com> wrote:

> Fix the num_slots value for most chips in the ad7173 driver. The number
> of slots corresponds to the number of CHANNEL registers on each chip.
> 
> Fixes: 4310e15b3140 ("iio: adc: ad7173: don't make copy of ad_sigma_delta_info struct")
> Signed-off-by: David Lechner <dlechner@baylibre.com>

Perhaps worth calling out that for many chips it seems to be falsely limiting
the number of slots which is a functionality limitation I think rather
than a bug.  The ones going the other way are more of a problem though!

Jonathan

> ---
> FYI, the bug actually existed before the commit I used for Fixes:, but
> that commit did major refactoring involving multiple drivers that would
> be too complicated to try to backport to older kernels.
> 
> I will try to send a separate fix to stable@ to fix the bug in it's
> original form on older kernels as that is just a one-liner.
> ---
>  drivers/iio/adc/ad7173.c | 37 +++++++++++++++++++++++++++----------
>  1 file changed, 27 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/adc/ad7173.c b/drivers/iio/adc/ad7173.c
> index dd9fa35555c79ead5a1b88d1dc6cc3db122502be..9c197cea11eb955becf4b9b97246379fa9c5da13 100644
> --- a/drivers/iio/adc/ad7173.c
> +++ b/drivers/iio/adc/ad7173.c
> @@ -771,10 +771,27 @@ static const struct ad_sigma_delta_info ad7173_sigma_delta_info_8_slots = {
>  	.num_slots = 8,
>  };
>  
> +static const struct ad_sigma_delta_info ad7173_sigma_delta_info_16_slots = {
> +	.set_channel = ad7173_set_channel,
> +	.append_status = ad7173_append_status,
> +	.disable_all = ad7173_disable_all,
> +	.disable_one = ad7173_disable_one,
> +	.set_mode = ad7173_set_mode,
> +	.has_registers = true,
> +	.has_named_irqs = true,
> +	.supports_spi_offload = true,
> +	.addr_shift = 0,
> +	.read_mask = BIT(6),
> +	.status_ch_mask = GENMASK(3, 0),
> +	.data_reg = AD7173_REG_DATA,
> +	.num_resetclks = 64,
> +	.num_slots = 16,
> +};
> +
>  static const struct ad7173_device_info ad4111_device_info = {
>  	.name = "ad4111",
>  	.id = AD4111_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 8,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -796,7 +813,7 @@ static const struct ad7173_device_info ad4111_device_info = {
>  static const struct ad7173_device_info ad4112_device_info = {
>  	.name = "ad4112",
>  	.id = AD4112_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 8,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -817,7 +834,7 @@ static const struct ad7173_device_info ad4112_device_info = {
>  static const struct ad7173_device_info ad4113_device_info = {
>  	.name = "ad4113",
>  	.id = AD4113_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 8,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -836,7 +853,7 @@ static const struct ad7173_device_info ad4113_device_info = {
>  static const struct ad7173_device_info ad4114_device_info = {
>  	.name = "ad4114",
>  	.id = AD4114_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 16,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -855,7 +872,7 @@ static const struct ad7173_device_info ad4114_device_info = {
>  static const struct ad7173_device_info ad4115_device_info = {
>  	.name = "ad4115",
>  	.id = AD4115_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 16,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -874,7 +891,7 @@ static const struct ad7173_device_info ad4115_device_info = {
>  static const struct ad7173_device_info ad4116_device_info = {
>  	.name = "ad4116",
>  	.id = AD4116_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in_div = 11,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -893,7 +910,7 @@ static const struct ad7173_device_info ad4116_device_info = {
>  static const struct ad7173_device_info ad7172_2_device_info = {
>  	.name = "ad7172-2",
>  	.id = AD7172_2_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_4_slots,
>  	.num_voltage_in = 5,
>  	.num_channels = 4,
>  	.num_configs = 4,
> @@ -926,7 +943,7 @@ static const struct ad7173_device_info ad7172_4_device_info = {
>  static const struct ad7173_device_info ad7173_8_device_info = {
>  	.name = "ad7173-8",
>  	.id = AD7173_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in = 17,
>  	.num_channels = 16,
>  	.num_configs = 8,
> @@ -943,7 +960,7 @@ static const struct ad7173_device_info ad7173_8_device_info = {
>  static const struct ad7173_device_info ad7175_2_device_info = {
>  	.name = "ad7175-2",
>  	.id = AD7175_2_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_4_slots,
>  	.num_voltage_in = 5,
>  	.num_channels = 4,
>  	.num_configs = 4,
> @@ -960,7 +977,7 @@ static const struct ad7173_device_info ad7175_2_device_info = {
>  static const struct ad7173_device_info ad7175_8_device_info = {
>  	.name = "ad7175-8",
>  	.id = AD7175_8_ID,
> -	.sd_info = &ad7173_sigma_delta_info_8_slots,
> +	.sd_info = &ad7173_sigma_delta_info_16_slots,
>  	.num_voltage_in = 17,
>  	.num_channels = 16,
>  	.num_configs = 8,
> 
> ---
> base-commit: 6742eff60460e77158d4f1b233f17e0345c9e66a
> change-id: 20250703-iio-adc-ad7173-fix-num_slots-on-most-chips-b982206a20b1
> 
> Best regards,